Machines such as excavators, backhoes, front shovels, and the like are used for earthmoving work. These earthmoving machines have work implements which consist of boom, stick, and bucket linkages. The boom is pivotally attached to the excavating machine at one end, and to its other end is pivotally attached a stick. The bucket is pivotally attached to the free end of the stick. Each work implement linkage is controllably actuated by at least one hydraulic cylinder for movement in a vertical plane. An operator typically manipulates the work implement to perform a sequence of distinct functions which constitute a complete earthmoving work cycle.
In a typical work cycle, the operator first positions the work implement at an excavation location, and lowers the work implement downward until the bucket penetrates the soil. Then the operator coordinates movement of several joints to bring the bucket toward the excavating machine. The operator subsequently curls the bucket to capture the soil. To unload the captured material, the operator raises the work implement, swings it transversely to a specified unloading location, and releases the soil by extending the stick and uncurling the bucket. The work implement is then returned to the excavation location to begin the work cycle again.
There is an increasing demand in the earthmoving industry to automate the work cycle of an excavating machine for several reasons. Unlike a human operator, an automated excavating machine remains consistently productive regardless of environmental conditions and prolonged work hours. The automated excavating machine is ideal for applications where conditions are unsuitable or undesirable for humans. An automated machine also enables more accurate excavation and compensates for lack of operator skill.
The major components for autonomous excavation, e.g., digging material, loading material into trucks, and recognizing loading receptacle positions and orientations, are currently under development. All of these functions are typically performed by software in computers. The planning steps required to determine a strategy for an optimal excavation is required. The specific location for each excavation, and the approach of the implement to the excavation start point must be determined so that the excavating process is performed as efficiently as possible.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.